A semiconductor electron beam device operates on the principle that a semiconducting material will normally have a low electrical conductivity impeding the flow of an electrical signal therethrough. Electrical carriers, however, can be generated in the semiconducting material in response to electron bombardment. This generation of electrical carriers, such as electron-hole pairs, increases the conductivity of the semiconducting material allowing the passage of an electrical signal therethrough.
For example, U.S. Pat. No. 4,993,033 to Lin entitled "High Power Fast Switch," discloses a switch for generating pulses of current to a load from a high voltage power source. A laser beam illuminates a cathode which stimulates the emission of pulses of electrons which illuminate a diamond target. These pulses of electrons cause the diamond target to become conductive thereby permitting electric current to pass from a voltage source through the target to a load.
U.S. Pat. No. 5,355,093 to Treado et al. entitled "Compact Microwave And Millimeter Wave Amplifier" discloses an electronic device for amplifying microwave or millimeter wave signals. In this device, the diamond target is mounted within an output circuit containing a resonant cavity and a quarter-wave choke section. A gated field emission array produces a density modulated beam of electrons which illuminates a thin diamond target in a diamond switch connecting a load to a high voltage source. Each electron in each pulse creates a large number of electron-hole pairs in the diamond target, and each surge of current produces an electromagnetic pulse at the load.
U.S. Pat. No. 5,355,380 to Lin et al. entitled "Compact Millimeter Wave Source" discloses a device wherein pulses of electrons illuminate a diamond switch. The diamond switch connects a high voltage source to a load, and electron pulses are provided by a klystron or a traveling wave tube.
The reference by Hofer et al. entitled "High Average Power Switching In Diamond," 20th International Power Modulator Symposium, 1992, discloses the use of a diamond as a high power solid state switch. This switch uses a low current electron beam to control the diamond switch. The high band-gap of diamond results in a high breakdown field or holding voltage, and the high thermal conductivity of diamond mitigates thermal runaway problems. This reference also discloses that electron beams with the required peak power can be generated with diamond surface emitters.
Notwithstanding the above mentioned references, there continues to exist a need in the art for improved semiconductor electron beam devices. This need is particularly critical in high temperature applications. This need is even more critical in applications requiring high frequency operation and fast turn-off times.